It is widely believed that after conquering Mundigak in 330 BC, Alexander the Great marched southeast with his army and laid out what is now Old Kandahar and named it Alexandria.
Others suggest that the foundation of the citadel was probably laid out during the Iron Age, and became a major fortress of the Achaemenid Empire.
The region became part of many empires, including the Mauryans (322 BC–185 BC), Indo-Scythians (200 BC–400 AD), Sassanids, Arabs, Zunbils, Saffarids, Ghaznavids, Ghorids, Timurids, Mughals, Safavids, Hotaks, and the Durranis.
It was one of the main cities of Arachosia, a historical region sitting in Greater Iran's southeastern lands and was also in contact with the Indus Valley civilization.
After the destruction of this old city all the remaining inhabitants were relocated to a nearby area which became known as "Naderabad" for a short time, named after Nader Shah.